A characterization of globally consistent databases and their correct access paths

The representative instance is proposed as a representation of the data stored in a database whose relations are not the projections of a universal instance. Database schemes are characterized for which local consistency implies global consistency. (Local consistency means that each relation satisfies its own functional dependencies; global consistency means that the representative instance satisfies all the functional dependencies.) A method of efficiently computing projections of the representative instance is given, provided that local consistency implies global consistency. Throughout, it is assumed that a cover of the functional dependencies is embodied in the database scheme in the form of keys.

[1]  Peter Honeyman,et al.  Testing satisfaction of functional dependencies , 1982, JACM.

[2]  Philip A. Bernstein,et al.  Computational problems related to the design of normal form relational schemas , 1979, TODS.

[3]  Alfred V. Aho,et al.  Efficient optimization of a class of relational expressions , 1979, TODS.

[4]  Philip A. Bernstein,et al.  Synthesizing third normal form relations from functional dependencies , 1976, TODS.

[5]  Yannis Vassiliou.  A formal treatment of imperfect information in database management , 1980 .

[6]  Philip A. Bernstein,et al.  What does Boyce-Codd Normal Form Do? , 1980, VLDB.

[7]  Alfred V. Aho,et al.  Equivalences Among Relational Expressions , 1979, SIAM J. Comput..

[8]  E. F. Codd,et al.  A relational model of data for large shared data banks , 1970, CACM.

[9]  Alfred V. Aho,et al.  The theory of joins in relational data bases , 1977, 18th Annual Symposium on Foundations of Computer Science (sfcs 1977).

[10]  David Maier,et al.  Discarding the Universal Instance Assumption: Preliminary Results , 1980, XP1 Workshop on Database Theory.

[11]  Peter Honeyman.  Extension Joins , 1980, VLDB.

[12]  Y. Edmund Lien.  Multivalued Dependencies With Null Values In Relational Data Bases , 1979, Fifth International Conference on Very Large Data Bases, 1979..

[13]  Joachim Biskup,et al.  Synthesizing independent database schemas , 1979, SIGMOD '79.

[14]  Yannis Vassiliou.  Functional Dependencies and Incomplete Information , 1980, VLDB.

[15]  Edward Sciore,et al.  The universal instance and database design , 1980 .

[16]  Mihalis Yannakakis,et al.  Equivalences Among Relational Expressions with the Union and Difference Operators , 1980, J. ACM.

[17]  Alfred V. Aho,et al.  Efficient optimization of a class of relational expressions , 1978, SIGMOD Conference.

[18]  David Maier,et al.  Testing implications of data dependencies , 1979, SIGMOD '79.

[19]  David Maier,et al.  Maximal objects and the semantics of universal relation databases , 1983, TODS.

[20]  E. F. Codd,et al.  A Relational Model for Large Shared Data Banks , 1970 .

[21]  Mihalis Yannakakis,et al.  Testing the Universal Instance Assumption , 1980, Inf. Process. Lett..

[22]  Ronald Fagin,et al.  A simplied universal relation assumption and its properties , 1982, TODS.

[23]  Yehoshua Sagiv,et al.  Can we use the universal instance assumption without using nulls? , 1981, SIGMOD '81.

[24]  E. F. Codd,et al.  Extending the database relational model to capture more meaning , 1979, ACM Trans. Database Syst..

[25]  Jeffrey D. Ullman,et al.  SYSTEM/U: a database system based on the universal relation assumption , 1984, TODS.

[26]  Sylvia L. Osborn.  Towards A Universal Relation Interface , 1979, Fifth International Conference on Very Large Data Bases, 1979..